NEW YORK – Japan-based Daiichi Sankyo and AstraZeneca today announced that their antibody drug conjugate fam-trastuzumab deruxtecan-nxki (Enhertu) has received Breakthrough Therapy Designation from the US Food and Drug Administration for the treatment of patients with advanced, HER2-positive gastric cancer.
The designation is expected to accelerate the review and approval of the antibody drug conjugate for a population of patients with a significant unmet need: HER2-positive metastatic gastric and gastroesophageal cancer patients, who have previously received multiple lines of treatment, including trastuzumab (Genentech's Herceptin). About one in five gastric cancers are HER2 positive, and patients whose disease progresses after the recommended first-line treatment of chemotherapy plus trastuzumab lack additional approved HER2-targeting treatment options.
Fam-trastuzumab deruxtecan-nxki works by delivering cytotoxic chemotherapy to HER2-expressing cancer cells by way of a HER2 monoclonal antibody attached to a tetrapeptide-based linker. The agent has already received accelerated approval in the US and in Japan for patients with previously treated, metastatic HER2-positive breast cancer. And for the gastric cancer indication, Daiichi Sankyo recently announced that it had submitted a supplemental new drug application to Japan's Ministry of Health, Labor, and Welfare.
Both the application in Japan and the breakthrough designation in the US are based on data from the Phase II DESTINY-Gastric-01 trial, as well as the Phase I trial published last spring in the Lancet Oncology. In the Phase II trial comparing fam-trastuzumab deruxtecan-nxki with investigator's choice of chemotherapy, the antibody drug conjugate demonstrated statistically significant and clinically meaningful improvement in objective response rate and overall survival, according to the drug sponsors. The full data from the trial will be presented during the 2020 American Society of Clinical Oncology Annual Meeting later this month.
Under the terms of Daiichi Sankyo and AstraZeneca's collaborative development of fam-trastuzumab deruxtecan-nxhi (referred to as simply trastuzumab deruxtecan outside the US), Daiichi Sankyo maintains exclusive rights to the agent in Japan alone. The two companies share rights in the rest of the world.